"I have an entirely different view," Romney told NRO of Akin's remarks. “What he said is entirely without merit and he should correct it."

Akin's comments threaten to shake up his effort to unseat incumbent Democratic Sen. Claire McCaskill this fall. That race is a key stepping stone in Republicans' effort to achieve the net gain of four seats they need to retake control of the Senate.

The controversy has already sparked national reverberations, however. Romney has lagged versus Obama with women voters, according to polls; his comments this morning follow on a spokeswoman's comments on Sunday quickly distancing Romney and presumptive Republican vice presidential nominee Paul Ryan from Akin. (Ryan, Democrats note, did co-sponsor with Akin a bill that would have redefined rape under portions of law.)

Massachusetts Sen. Scott Brown (R) called on Akin to resign his Senate nomination.

"While Congressman Akin may have addressed his statement, like many men and women I strongly disapprove of his original comments — and the sentiments behind them," said former Virginia Sen. George Allen (R), who's trying to reclaim his old seat this fall.

In a statement and a Tweet, conservative congressman Todd Akin says he "misspoke" during a local TV interview in which he made comments about "legitimate rape" and abortion.